1. Field of the Invention
The present invention relates generally to the mass transport of articles, such as cylindrical containers, from a first elevation to a second elevation, and, particularly, to a method and apparatus for transporting articles from a level orientation on a first elevation to a level orientation on a second elevation by initially conveying the articles onto a foraminous belt, moving the belt over a low pressure containing plenum having a curved supporting surface to secure the articles to the belt and the belt to the surface by means of vacuum, moving the belt and secured articles over the curved surface to an inclined orientation, securing the articles to the inclined belt by means of a second parallel inclined belt to thus contain the articles between the spaced moving belts while being conveyed in an inclined orientation, and again moving the foraminous belt from an inclined to a level orientation while passing over a second low pressure plenum having a curved supporting surface to again secure the articles to the foraminous belt and the belt to the surface while undergoing the transition from the inclined orientation to the level orientation.
2. Description of the Prior Art
In many manufacturing operations, and particularly in the manufacture of cylindrical containers such as two piece ferrous or aluminum cans, it is necessary to mass transport great numbers of articles. While some conveying systems provide for single line, i.e., single file, transport of the articles, the great number of cans or other articles being transported requires extremely high linear speeds to maintain line speeds up to 2000 articles a minute. Thus, in many instances, the articles are mass conveyed across fairly broad conveyer systems rather than in a single file arrangement. When empty, articles such as cans tend to be marginally unstable and may be toppled over if not handled with care.
Conventionally, articles such as those of concern are mass conveyed between different elevations by means of a belt conveyer inclined with a very small slope. Accordingly, in order to gain any substantial difference in elevation, the conveyer must extend for great distances. If additional slope is provided, the cans tend to slide on the belt, fall over, or jam at the discontinuity between the level and sloped portions. Since belts tend to assume a catenary curve between supports, and to approach a straight line between rollers with appropriate tension, the transition from one belt to another belt under tension tends to be in the form of discontinuity rather than a gradual curve.
It is also known to secure articles such as those with which the instant invention is concerned to a perforated rotating drum by means of a vacuum in the drum. Such drums are usually utilized to engage an article, carry the article around the drum for 180.degree., and then deposit the article on another conveyor system, thereby inverting the article. Particularly for processes such as washing, rinsing, coating etc. such inversion is desirable.
Still another verticle transport method usually utilized with single line transport is spaced, parallel belts moving at the same linear velocity. These belts sandwich the articles therebetween, and transport the articles to another level. However, such transport systems using parallel belts are subject to the above discussed directional discontinuties between a level and substantially inclined path. By utilizing the spaced belts on a single line section, individual cans may be transported from the level to the vertical or inclined belts. Mass transport as opposed to single line transport, between spaced belts is clearly a much more difficult problem.